Process for vaccine preparation

Abstract

A vaccine comprising an antigen selectively adsorbed onto erythrocytes possessing their natural surface characteristics. When the antigen is the K88a,b/adhesion factor of E. coli and the erythrocytes are chicken erythrocytes, the vaccine is especially suitable for reducing the incidence of neonatal diarrhoea in pigs if it is administered parenterally to a sow about three weeks prior to parturition.

What is claimed is: 
     
       1. A process for the preparation of a vaccine for parenteral administraion to pregnant mammals as a means for reducing the incidence of neonatal diarrhoea, in which process K88a,b/adhesion factor of an enteropathogenic strain of E. coli is adsorbed from a cell-free aqueous solution onto erythrocytes possessing their natural surface characteristics, the ratio of adsorbed K88a,b/adhesion factor to the volume of erythrocytes present being in the range 125 to 800 hemagglutination units per ml, and the composition so formed is rendered storable by the addition thereto of a preservative such as sodium azide or formalin. 
     
     
       2. A process as claimed in claim 1, wherein said erythrocytes are chicken erythrocytes. 
     
     
       3. An injectable vaccine prepared by a process as claimed in claim 1 or claim 2.